Comparison of hemodynamic responses to nifedipine and nitroprusside in severe chronic congestive heart failure.

The hemodynamic effects of 20 to 40 mg of oral nifedipine were compared with those of intravenous nitroprusside in 11 patients with severe chronic congestive heart failure (CHF). In each patient, both drugs were administered to produce similar reduction of systemic vascular resistance (SVR) (29 +/- 13% with nifedipine and 29 +/- 12% with nitroprusside, difference not significant [NS]). At this comparable decrease in systemic vascular resistance, significant differences in hemodynamic responses to both drugs were noted: Nifedipine caused a smaller increase in cardiac index (20 +/- 20% vs 40 +/- 24%, p less than 0.02) and a larger decrease in mean blood pressure than nitroprusside (16 +/- 9% vs 8 +/- 10%, p less than 0.05). In addition, nifedipine produced a smaller decrease in mean pulmonary artery wedge pressure (13 +/- 24% vs 36 +/- 21%, p less than 0.001) and pulmonary vascular resistance than nitroprusside (6 +/- 42% vs 26 +/- 46%, NS). Mean right atrial pressure decreased with nitroprusside, from 10 +/- 7 to 5 +/- 3 mm Hg (p less than 0.05), but not with nifedipine (10 +/- 7 mm Hg before and after nifedipine administration, NS). Left ventricular stroke work index increased with nitroprusside (20 +/- 8 to 27 +/- 9 g-m/m2, p less than 0.05), but did not change with nifedipine (21 +/- 9 vs 21 +/- 10 g-m/m2, NS). These data show that nifedipine has an arteriolar dilatatory action in patients with CHF. However, compared with nitroprusside, nifedipine had a significantly larger hypotensive effect and had a lesser effect on right and left ventricular filling pressure, cardiac output and left ventricular function.